Recent content by OsvaL

I have the exactly same problem with my Macintosh Classic. The only way it will boot the OS is plugging it bypassing the ground pin with an adapter. Other symptom I have is that when I connect the ADB keyboard only some keys actually work. Don’t have the knowledge to fix this issue.

I have a similar issue with my Macintosh Classic. The only way it will turn on is plugging it without the ground pin using an adapter. When I connect an ADB keyboard some keys don’t work, I think is related to this issue. I never tried to solve this situation since I don’t have the knowledge to...

Thank you all for the tips and recommendations!

Thank you very much @LaPorta now I can confirm this. I was looking at the sorrounding BV4 transistors and they were connected exactly the same way as the one I burnt. Then I started looking on some high resolution photos I found on the internet and with some Photoshop I was able to make the...

Thanks a lot @LaPorta  I have another floppy drive from a Performa (not compatible with the Classic) I may take the part from its PCB.

 You are right. When I was trying to troubleshoot my floppy drive, I left it on top of its bracket without noting it was touching the PCB producing a short. Some electronic component broke and smoke escaped from it. I don't know the specification of the part that broke so I can't change it. If...

I have the exactly same problem with my floppy drive (Sony 1.44 Macintosh Classic) under System 6.0.8.

Hi @PB145B you are right. It's the same exactly one. So basically that is my main and huge problem. Thank you all of you for give me this very important clue. 

BTW, the floppy drive has been serviced, the heads cleaned with isopropyl alcohol and lubricated according to the tutorials I've seen in YouTube. As I said before, as long it's not installed in its bracket, everything works fine.

Hello, Does anyone know why the 1.44 floppy drive from my Macintosh Classic only reads floppy disks when it's not installed on the brackets? While it's connected without the brackets it reads very reliably. As soon as I install the floppy drive in its bracket, the drive reads the system...

Finally in some way, I found the solution to the problem. Is not quite elegant but at least it allows me to play with my computer. For some reason when I use an adapter to plug the computer to the power outlet without connecting the ground pin, the voltages remain stable, both the 5V and 12V...

The first thing you should do to start diagnosing your Mac is replacing all the capacitors from the logic board and the analog board. Even if they look fine they don't bulge on the top part but they leak from the bottom. Those different patterns you see that change every time you insert a RAM...

I'm posting an image of my analog board just in case someone notice something.

I think that big heatsink is attached to a power transistor. I didn't check the little board on the back of the CRT. I'm taking note to check it next time.

Another video, this time booting the Classic using a heater.